The northern boundary of the Palm Island Inshore reporting zone extends east from the north-west bank of the Seaforth Channel mouth, just south of Hinchinbrook Island, to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.
The southern boundary of the Palm Island zone extends eastward from the southern boundary of the Herbert River Basin to just east of the Palm Island Group and runs north to the Wet Tropics NRM marine region boundary at the junction with the offshore waters boundary.
The major river discharging into the Palm Island zone is the Herbert River. Several sub-catchments, including the Seymour River, also discharge into the Palm Island inshore zone.
Water quality in the Palm Island zone is affected by plumes of sediments, nutrients and pesticides from rivers discharging directly into the zone but also from the plumes of southern rivers, particularly the Burdekin River the mouth of which is approximately 180 km to the south-east.
The area includes the Palm Island group located approximately 17 km east of the mainland. The Palm Island Group includes Orpheus Island, Pelorus Island, Fantome Island, Palm Island, and Havannah Island. These islands provide fringing shallow water environments that support coral reef ecosystems and reef seagrass meadows.
The overall grade for Palm Island zone remained ‘moderate’ with the score declining to 51 in 2017-18 from 57 the previous year.
The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.
The water quality grade in 2017-18 for the Palm Island inshore zone was ‘moderate’ and scored 53.
Water quality grades are based on water quality guideline trigger values established for the waters of the Great Barrier Reef Marine Park that, if exceeded, identify the need for management responses. The guidelines are not targets or assessments of pollutant loads entering the marine environment. The results are derived from in-situ water samples and water quality loggers at two inshore locations and passive pesticide samplers located Lucinda jetty.
The water clarity score of 57 (‘moderate’) in the Palm Island zone is comprised of total suspended solids (‘poor’) and turbidity (‘good’) indicators.
Nutrients scored 42 (‘moderate’) in the Palm Island zone, comprising of ‘poor’ for oxidised nitrogen (NOx) and particulate nitrogen (PN) and a ‘good’ for particulate phosphorus (PP).
The chlorophyll a score in the Palm Island zone was 46 (‘moderate’).
Using the pesticide risk metric pesticides were graded “very good” and scored 86, equating to 99.3 percent of species protected.
The overall coral grade in 2017-18 for the Palm Island inshore zone is 49 (‘moderate’). The coral index in the Palm Island zone has remained a ‘moderate’ grade since 2014-15 and the index score of 49 has remained unchanged since 2015-16.
The coral grade is comprised of the density of juvenile hard corals score of 51 (‘moderate’), the macroalgae cover score of 32 (‘poor’), the coral cover score of 37 (‘poor’), the change in coral cover score of 60 (‘moderate’), and the coral community composition score of 63 (‘good’).
The Palm Island coral condition score for 2017-18 remained unchanged from the previous year. Slight declines of the juvenile density and the species composition indicators occurred. The high macroalgae cover is the primary factor limiting coral condition in the Palm Island zone and has remained ‘poor;’ over the last three reporting periods. The macroalgae indicator scores remained low due to high cover of macroalgae observed at most reefs inshore of the Palm Island group.
More information on recent changes in coral indicators and the relationships with environmental conditions are provided in the latest Marine Monitoring Program coral report Thompson et al. (2019).
There is no current seagrass monitoring undertaken in the Palm Island Zone and consequently there is no seagrass grade available for the Report Card in the Palm Island Zone.
The fish index is currently under development and will be available in future report cards.
Thompson A, Costello P, Davidson J, Logan M, Greg Coleman (2019) Marine Monitoring Program. Annual Report for inshore coral reef monitoring: 2017 to 2018. Australian Institute of Marine Science, Townsville.132 pp.